iOS6 UICollectionView and UIPageControl - How to get visible cell?

I struggled with this for a while as well, then I was advised to check out the parent classes of UICollectionView. One of them happens to be UIScrollView and if you set yourself up as a UIScrollViewDelegate, you get access to very helpful methods such as scrollViewDidEndDecelerating, a great place to update the UIPageControl.

I would recommend a little tuned calculation and handling as it will update page control immediately in any scroll position with better accuracy.

The solution below works with any scroll view or it subclass (UITableView UICollectionView and others)

in viewDidLoad method write this

scrollView.delegate = self

then use code for your language:

Swift 3

func scrollViewDidScroll(_ scrollView: UIScrollView) 
    {
       let pageWidth = scrollView.frame.width
       pageControl.currentPage = Int((scrollView.contentOffset.x + pageWidth / 2) / pageWidth)
    }

Swift 2:

func scrollViewDidScroll(scrollView: UIScrollView) 
{
   let pageWidth = CGRectGetWidth(scrollView.frame)
   pageControl.currentPage = Int((scrollView.contentOffset.x + pageWidth / 2) / pageWidth)
}

Objective C

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat pageWidth = self.collectionView.frame.size.width;
    self.pageControl.currentPage = (self.collectionView.contentOffset.x + pageWidth / 2) / pageWidth;
}

You must setup yourself as UIScrollViewDelegate and implement the scrollViewDidEndDecelerating:method like so:

Objective-C

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    CGFloat pageWidth = self.collectionView.frame.size.width;
    self.pageControl.currentPage = self.collectionView.contentOffset.x / pageWidth;
}

Swift

func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {

    let pageWidth = self.collectionView.frame.size.width
    pageControl.currentPage = Int(self.collectionView.contentOffset.x / pageWidth)
}